Approximate "~" sizes in Open Cut List

I’m fairly new at Sketchup and really new to the Open Cut List extension.

When generating a parts list for my drawing I found some surprises in the size of some of my parts. Several are listed as approximate size with the tilde “~” symbol. (~3/4, ~9/16, etc.)

However when I go back to the model and check their dimension with the tape measure tool they appear to be the correct size.

After reading a few other posts I checked and my units are set to fractional with 1/64 precision.

What am I doing wrong and how do I fix it?

Hall Table.skp (173.2 KB)

On my phone so can’t check your model now, but I’d speculate that component axes aren’t aligned with the edges of the boards.

The tilde indicates you have dimensions that fall between precision units. In your case it looks like this is due to what might be an error you induced early in the modeling by imprecise placement of one side of the case compared to the other. I expect you wanted the case to be 36 in. wide. Since you didn’t get this placement done precisely, other dimensions such as the lerngth of the drawer fronts is off.

You’ve also got components with oddball dimensions such as in the case of the Front stile.

If you zoom in very close you can see that the top edge of the stile is not aligned on axis with the bounding box. That implies some off-axis drawing.

You could fix the model or maybe get away with ignoring the tildes. Personally, being kind of AR about this sort of thing, I would fix the model.

Keep in mind that the cutlist extensions are only reporting what you have modeled.

FWIW I couldn’t leave it alone. I redid the model to get rid of the approximate dimensions and to make sure all fractions should be easy to deal with. Nothing smaller than 1/16 in.

Screenshot - 9_6_2020 , 6_26_05 PM

I did change the construction a little to make it cleaner and stronger. I do think the top needs some help. I monkeyed around with it a bit more and made a few changes. Could still use more tweaking, I think.

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I’m sure you’re right about me introducing the imprecision. But how? and more importantly how do I avoid doing it again?

Your answer is spot on, but it does drive me to even more questions.

How did you get that little popup window with the width, height, and depth?

How did you find the imprecision? I looked, but didn’t find it. Using both the tape measure and the dimension tool measuring endpoint to endpoint, they both display 36" where yours shows 35.998763.

Hos did you find that? It’s so close. What led you to looking there? I.e. How could I have found this myself? How do I fix it?

Thanks for the AR scrutiny. I most definitely want to fix the model and even more so want to understand how to avoid these types of errors in the future. And since I know I have many more mistakes to make, how can I find them. Not that I don’t appreciate the help, I DO. I just would like to learn from these mistakes and therefore be less dependent.

Love it!

Did you adjust mine, or start over? Which I am considering doing myself. Mostly as a learning experience.

I’m all for improvement. What changes did you make? Especially any that make it stronger. What is needed on the top? I see you made it a bit larger with some overhang, which I like. Anything else?

What other tweaking do you suggest?

I don’t see the dados in your model. Are they not there, or just hidden in this view? Was that overkill on my part? I was planning to add some edge banding to hide the plywood edges but just hadn’t added that to the model.

If you were starting to design a project like this from scratch, what would be your basic sequence? Would you start with the top to set the basic dimensions? Then move to the frame and panel sides? How do you approach something like this? I’m sure it varies from one project to the next and is personal preference, but is there a common efficient methodology?


I’ve been away from this model for a while, but back to it now.

I asked several questions before but have not seen any answer. If you have time I’d appreciate a response to those questions asked previously.

Also, in your version of the model, how are the shelves attached? pocket screws? hidden dadoes? or something else?

Thanks for whatever time you can take to assist. I truly appreciate it.

Turn off Length snapping, set appropriate units for the model size and set Display Precision as fine as it will go for the units so you can see if you have allowed imprecision to creep in. Also make sure you are entering precise dimension when needed and that you are staying on axis with the modeling.

That’s from a plugin that, as I recall, the author withdrew. I still have the thing though.

I was able to spot the imprecise dimensions by doing what I indicated above with Display Precision and running a cut list to look at all of the parts in list form.

Years of looking at other people’s models and looking for things like apparently thick edges. That’s easier to do if you set Profiles to 1 in the style and use Monochrome face style so the textures don’t mask these problems.

Started over. I generally find it easier to do that than chase through a model looking for things to fix.

It’s been a long time and I didn’t keep the model so I don’t remember all the details. I basically modeled the parts to fit correctly.

The dadoes were there. The shelves were one piece and the vertical dividers were set into shallow dadoes top and bottom. The dadoes were stopped back half an inch or so from the front edge of the shelves so they don’t show.

I would generally a model like this with the front left leg. It would be made into a component, copied to the back and the copy flipped in the green direction. Rails would be added between those verticals and a panel added. Each part would be a component and when components are the same, I would make copies to save myself work. Once the side assembly is complete I would copy all of that over to the right side and flip along the red direction to mirror these components. Then I would add the pieces to fit in between. All joinery would wait until the parts of the model are all created as components. The top would go on last and be modeled in place to ensure it is centered.

It does vary from user to user. The key thing is to use a logical and methodical work flow.

Since those shelves are fixed, I would have most likely used loose tenons (Dominoes) between the shelves and the legs. Nothing against pocket screws but I usually prefer other joinery methods when I can do them.

FWIW, most likely the only plywood I would specify in a project like this would probably be the side panels, back panel, and the drawer bottoms. If I had to do plywood for the shelves and vertical dividers, they would get hardwood edging, instead of just a veneer.

So VERY helpful!!! Thank you so much!

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